Clinical data links oral bisphosphonates to increased jaw necrosis, according to research at the University Of Southern California School Of Dentistry. A study published today in January 1 Journal of the American Dental Association (JADA) is among the first to acknowledge that even short-term use of common oral osteoporosis drugs such as Fosamax may leave the jaw vulnerable to devastating necrosis.
Osteoporosis, or loss of bone density, currently affects 10 million Americans. And TV commercials like the one for Boniva featuring Sally Field ("I've got this one body") tend to popularize and even glamorize anti-osteoporosis drugs.
Fosomax is the most widely prescribed oral bisphosphonate, ranking as the 21st most prescribed drug on the market since 2006, according to a 2007 report released by IMS Health.
Post-menopausal women and cancer patients including prostate and breast cancer patients are among those most likely to take bisphosphates by prescription. Cancer patients, especially those who are hormonally suppressed or taking chemotherapy, are at serious risk of developing osteoporosis.
Today, cancer patients are more likely to take a potent, intravenous form of bisphosphonate, called Zometa, rather than an oral form such as Fosomax, Actonel, or Boniva, Some cancer patients have been quite widely informed for about the past 5 years that bisphosphonates do present a risk of osteonecrosis of the jaw.
But there has been some confusion and uncertainty over whether this risk applies as much with the oral forms like Fosamax as with the intravenous drugs such as Zometa.
First large study of oral bisphosphonates and jaw damage
"Oral Bisphosphonate Use and the Prevalence of Osteonecrosis of the Jaw: An Institutional Inquiry" is the first large study in the U.S. to investigate the relationship between oral bisphosphonates and jaw bone death, said principal investigator Parish Sedghizadeh, assistant professor of clinical dentistry with the USC School of Dentistry.
After controlling for referral bias, 9 of 208 healthy School of Dentistry patients who take or have taken Fosamax for any length of time were diagnosed with osteonecrosis of the jaw (ONJ).
The study’s results contrast with drug makers' prior assertions that bisphosphonate-related ONJ risk is only noticeable with intravenous use of the drugs, not oral usage, Sedghizadeh said. "We’ve been told that the risk with oral bisphosphonates is negligible, but four percent is not negligible," he said.
Till now, most doctors prescribing bisphosphonates have not told patients about any oral health risks associated with the use of the drugs. But even short-term usage poses a risk due to the drug’s tenacious 10-year half life in bone tissue.
Lydia Macwilliams of Los Angeles said no one told her about the risk posed by her three years on Fosamax until she became a patient of Sedghizadeh at the School of Dentistry.
"I was surprised," she said. "My doctor who prescribed the Fosamax didn’t tell me about any possible problems with my teeth." Macwilliams was especially at risk for complications because she was to have three teeth extracted due to infection. This type of dental infection is a biofilm bacterial process, meaning that the bacteria infecting the mouth and jaw tissues reside within a slimy matrix that protects the bacteria from many conventional antibiotic treatments, and bisphosphonate use may make the infection more aggressive in adhering to the jaw, Sedghizadeh said.
The danger is especially pronounced with procedures that directly expose the jaw bone, such as tooth extractions and other oral surgery. After her extractions, two of the three extraction sites had difficulty healing, Macwilliams said. Luckily, with treatment as well as the rigorous oral hygiene regimen USC dentists developed especially for patients with a history of bisphosphonate usage, the remaining sites slowly but fully healed. "It took about a year to heal," she said, “but it’s doing just fine now.”
Sedghizadeh hopes to have other researchers confirm his findings and thus encourage more doctors and dentists to talk with patients about the oral health risks associated with the widely used drugs. The results confirm the suspicions of many in the oral health field, he said. "Here at the School of Dentistry we’re getting two or three new patients a week that have bisphosphonate-related ONJ," he said, "and I know we’re not the only ones seeing it."
SOURCES AND LINKS
Doctors link bisphosphonates drugs, used against osteoporosis and cancer, to jawbone necrosis May 2004
Concern over osteoporosis drug Australian Broadcasting Corporation Broadcast: 11/12/2007
OSTEONECROSIS OF THE JAW (ONJ) 2006 (MS Word document) by Laurence C. Reichel, D.D.S.
Silent risk of osteoporosis in men with prostate cancer PSA Rising 2004
Parish Sedghiuzadeh's professional page.